Exploring the band structure of Wurtzite InAs nanowires using photocurrent spectroscopy

Abstract

We use polarized photocurrent spectroscopy in a nanowire device to investigate the band structure of hexagonal Wurtzite InAs. Signatures of optical transitions between four valence bands and two conduction bands are observed which are consistent with the symmetries expected from group theory. The ground state transition energy identified from photocurrent spectra is seen to be consistent with photoluminescence emitted from a cluster of nanowires from the same growth substrate. From the energies of the observed bands we determine the spin orbit and crystal field energies in Wurtzite InAs.

Sulfur-Passivated InSb Nanowires for Infrared Photodetectors

“…It indicates that the S element plays the role of a surface passivator and reduces surface state density, which is consistent with the results of S surface passivation in the literature. 15,27,34,39 In the case of 4% S, a very small peak of the In 2 O 3 crystalline phase was still detected, despite the fact that many attachments have formed on the NW surface. This probably arises from a small amount of In 2 O 3 particles at the bottom of the product, which were grown from the excessive In powder that was not involved in the chemical reaction.…”

Growth, Crystal Structure, and Photoluminescent Properties of Dilute Nitride InAsN Nanowires on Silicon for Infrared Optoelectronics

“…Compared to thin-film counterparts, InAs NW-based IR detectors have a limited spectral sensitivity shifted toward higher energies, which restricts their functionality . This is attributed to the crystal structure of the self-induced InAs NWs, which tend to crystallize in a metastable wurtzite (WZ) structure with a larger band gap compared to the zinc blende (ZB) structure stable in a bulk material . A significant increase in the long-wavelength sensitivity (5.7 μm at 5 K) has been achieved so far only for InAsSb-based NW photodetectors .…”

“…13 This is attributed to the crystal structure of the self-induced InAs NWs, which tend to crystallize in a metastable wurtzite (WZ) structure with a larger band gap compared to the zinc blende (ZB) structure stable in a bulk material. 14 A significant increase in the long-wavelength sensitivity (5.7 μm at 5 K) has been achieved so far only for InAsSb-based NW photodetectors. 15 T h i s c o n t e n t i s However, incorporating heavy Sb atoms into the InAs lattice requires significantly reduced growth temperatures and can lead to the opening of resonant Auger recombination channels due to an increased spin−orbit splitting in the valence band.…”

Wurtzite InAs Nanocrystals with Short-Wavelength Infrared Emission Synthesized through the Cation Exchange of Cu3As Nanocrystals

“…21,22 Compared to the zinc-blende structure with T d point group symmetry, the characteristic feature of the wurtzite structure (C 6v point group symmetry) is the crystal field, causing the formation of three doublydegenerate hole bands at the topmost valence band when combining with the spin−orbit interaction. 23 These three hole bands are the so-called A (heavy hole), B (light hole), and C (split-off hole) bands, with Γ 9v , Γ 7v , and Γ 7v symmetries, respectively. 24 The resulting A exciton is in-plane-polarized, while B and C excitons are out-of-plane-polarized.…”

“…Among the group III–V semiconductors, bulk indium arsenide (InAs) is a direct semiconductor with a narrow bulk band gap of ∼0.35 eV . Colloidal InAs NCs exhibit widely tunable emitting wavelengths ranging from the visible region to the short-wavelength infrared (SWIR, 1000–2000 nm) region by size adjustment and stand out as an infrared-active candidate material for efficient SWIR LEDs, biological imaging, photovoltaics, and sensing applications. ,, InAs in bulk is known to crystallize into two distinct phases, a stable cubic zinc-blende phase and a metastable high-temperature hexagonal wurtzite phase. , Compared to the zinc-blende structure with T d point group symmetry, the characteristic feature of the wurtzite structure ( C 6 v point group symmetry) is the crystal field, causing the formation of three doubly-degenerate hole bands at the topmost valence band when combining with the spin–orbit interaction . These three hole bands are the so-called A (heavy hole), B (light hole), and C (split-off hole) bands, with Γ 9 v , Γ 7 v , and Γ 7 v symmetries, respectively .…”